2025-10-05

SNES Emudev

• #emulation
• #programming

This page is intended to collect information about developing emulators for the SNES.

Architecture

CPU

Uses a Ricoh 5A22 CPU, which is based on the WDC W65C816S, in turn an evolution of the classic 6502 ISA, with 16 bit functionality.

Assembly

References

• https://undisbeliever.net/snesdev/65816-opcodes.html

Resources

Docs

• https://novasquirrel.github.io/SnesInstructionCycleTool/

  • Good information about the timing of each CPU instruction.

Tests

• https://github.com/SingleStepTests/65816

  • Contains instruction tests for the 65816 Processor.

Reference Emulators

• https://github.com/MiSTer-devel/SNES_MiSTer

  • Verilog implementation that claims to be cycle accurate.